A significant portion of the human genome encodes genes that transcribe long nonprotein-coding RNAs (lncRNAs). A large number of lncRNAs localize in the nucleus, either enriched on the chromatin or localized to specific subnuclear compartments. Nuclear lncRNAs participate in several biological processes, including chromatin organization, and transcriptional and post-transcriptional gene expression, and also act as structural scaffolds of nuclear domains. Here, University of Illinois researchers highlight recent studies demonstrating the role of lncRNAs in regulating gene expression and nuclear organization in mammalian cells. In addition, they update current knowledge about the involvement of the most-abundant and conserved lncRNA, metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), in gene expression control.
Model Depicting Potential Mode of Action of
Metastasis-Associated Lung Adenocarcinoma Transcript 1 (MALAT1)
(A) MALAT1, along with MALAT1-interacting proteins, such as unmethylated Pc2, relocates genomic loci from the nucleoplasm or other nuclear domains to the nuclear speckle periphery and promotes the activation of corresponding genes. (B) MALAT1 interacts with multiple chromatin modifiers and transcription factors to modulate transcription. (C) MALAT1 serves as a scaffold in nuclear speckles for RNA-binding proteins (RBPs) and influences various co- and post-transcriptional processes